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About Our Research

Physics and Chemistry of Polymers.

Our research is focused on the design and characterization of functional polymer films. Our work can be applied to low-cost solar cells, semiconductor device manufacturing, membranes, anti-fouling coatings, and biosensing. The following paragraphs introduce several core thrusts in our group.

Projection Lithography.

We are studying polymer imaging materials for optical lithography, which is the patterning technique used to define microelectronics circuitry. The goals of this program are to measure the chemical reactions that generate the images, build process models that incorporate ultra-thin film properties, and develop high-throughput screening methods for new materials.

Nanopatterning.

We are studying block copolymer self-assembly for applications in low-cost nanopatterning of semiconductor devices. The goal of this research effort is to control self-assembly in three-dimensions by tuning interactions at the free surface and substrate interfaces.

Solar Cells.

We are studying the variables that control power-conversion efficiency in polymer-based solar cells. We build model devices for fundamental studies of photocurrent generation using top-down lithography. Ultimately, our goal is to improve the device efficiency by controlling the active layer morphology.

Thin Film Physics.

We have several ongoing projects that focus on the fundamental physics of thin polymer films. These studies include directed dewetting, suppressing phase separation in blends, self-healing films, and anti-fouling coatings.

Recent News

July 2014
June 2014
May 2014
  • Gila visits University of Minnesota to speak about GISAXS at IPrime.
  • Abhijit presents at EIPBN.
  • Hanh is awarded a SURF fellowship for the summer!

April 2014
  • Gila speaks at the Faculty Senate Lecture Series on "Flexible Solar Cells."
  • Saeed defends his MS thesis "Tuning the Functionality of Printed Conductive Polymers using Proximity Ion Beam Lithography." Congrats Saeed!
  • Nikki defends her PhD thesis "Nanostructured Polymer Films for Electronics." Congrats Dr. Nikki!
  • Gila visits the Chemical and Biomolecular Engineering department at NCSU.

March 2014
  • Indranil, Nikhila, and Gila all speak at the Annual Meeting of the American Physical Society.

February 2014
  • Abhijit presents his work with photoresists at SPIE Lithography. Read about his work here.

People

Dr. Gila Stein

  • Ernest J. and Barbara M. Henley Assistant Professor of Chemical & Biomolecular Engineering, 2009-Present.
  • Joint appointments with the Chemistry Department and Materials Program.
  • NRC-NIST Postdoctoral Fellow, 2007-2008
  • Ph.D. Chemical Engineering, University of California, Santa Barbara, 2006
  • B.S. Chemical Engineering, Drexel University, 2002

E-mail: gestein "at sign" uh.edu



Graduate Students

Nikhila Mahadevapuram

  • B.S. Chemical Engineering, National Institute of Technology, Warangal, India, 2008
  • Research Interests: Organic photovoltaics, block copolymer self-assembly.
  • E-mail: nmahadev "at sign" uh.edu

Indranil Mitra

  • Ph.D. Mathematical Physics, Saha Institute of Nuclear Physics, Kolkata, India
  • Research Interests: Directed self-assembly of block copolymers, nanopatterning, biomarker detection.
  • E-mail: imitra "at sign" uh.edu

Abhijit Patil

  • M.S. Chemical Engineering, University of Kentucky, 2009
  • B.S. Chemical Engineering, University Institute of Chemical Technology, Mumbai, India, 2007
  • Research Interests: Controlling image formation in photoresist thin films
  • E-mail: abhijit7.patil "at-sign'' gmail.com

Saeed Ahmadi Vaselabadi

  • B.S. Chemical Engineering, Sharif University of Technology, Tehran, Iran, 2012
  • Research Interests: Organic photovoltaics, nanopatterning.
  • E-mail: sahmadivaselabadi "at sign" uh.edu

Adeline Mah

  • B.S. Chemistry, University of Houston, December 2012
  • Research Interests: Lithography, surface chemistry, biosensors
  • E-mail: huizhen89 "at sign" gmail.com

David Truong

  • B.S. Chemical Engineering, Clemson University, May 2013
  • Research Interests: Block copolymers, membranes.
  • E-mail: pvtruong "at sign" gmail.com


Undergraduate Students

Pantea Afzali

  • B.S. Chemical Engineering, University of Houston, Dec 2014 (Exp.)
  • Research Interests: Polymer blends, thin films.
  • E-mail: pafzali "at sign" uh.edu

Hanh Phan

  • B.S. Chemical Engineering, University of Houston, Dec 2015 (Exp.)
  • Research Interests: Polymer blends, thin films, and lithography.
  • E-mail: htphan5 "at sign" uh.edu

UH Undergraduate Alumni

  1. Thao Dinh, B.S. Chemical Engineering, May 2011
  2. Thai Vu, B.S. Chemical Engineering, May 2011
  3. Trang Pham, B.S. Chemical Engineering, December 2011
  4. Gus Rajaendran, B.S. Chemical Engineering, May 2012
  5. Loc Ngo, B.S. Chemical Engineering, May 2012
  6. Adeline Mah, B.S. Chemistry, December 2012
  7. Sean Hensarling, B.S. Chemical Engineering, May 2013
  8. Xidong Lin, B.S. Chemistry, May 2014

REU Alumni

  1. Makenzie Dixon, Trinity University, Summer 2009
  2. Amara Enemuo, City College of New York, Summer 2009
  3. Leslie Scrof, Louisiana State University, Summer 2010
  4. Alona Bozhchenko, Rice, Summer 2011

UH Graduate Alumni

  1. Dr. Suchanun Moungthai, Ph.D. Chemical Engineering, August 2012. (Intel)
  2. Dr. Ginusha Perera, Ph.D. Chemical Engineering, December 2012. (Intel)

Visitors

  1. Akil Chittaluru, Klein Oak High School, Summer 2011
  2. Steven Tsai, St. Mark's School of Texas, Summer 2012
  3. Mukund Kabra, Colleyville Heritage High School, Summer 2013

The Lab

Facility & Equipment

  • 1,400 square feet of newly renovated lab space
  • Three chemical fume hoods
  • J.A. Woolam M-2000 spectroscopic ellipsometer with focusing optics and Instec heat stage
  • Nikon LV150 reflected light microscope (BF/DF) with digital camera
  • Brewer CEE 200CB spin coater and bake plate
  • Dataphysics OCA 15EC contact angle goniometer
  • Keithly 2601A source measure unit
  • HE-453-2 Vacuum Atmospheres glove box equipped with SCS spin coater
  • Oriel 150W solar simulator
  • Two VWR vacuum ovens
Other Resources

Publications

Journal Articles
    2014
  1. I. Mitra,* X. Li,* S.L. Pesek, B. Makarenko, B.D. Lokitz, D. Uhrig, J.F. Ankner, R. Verduzco, G.E. Stein, ``Thin Film Phase Behavior of Bottlebrush/Linear Polymer Blends,'' Macromolecules, Article ASAP, 2014. [DOI]
    • *Equal Contribution.
  2. G.E. Stein, N. Mahadevapuram, I. Mitra, ``Controlling Interfacial Interactions for Directed Self Assembly of Block Copolymers,'' Journal of Polymer Science Part B: Polymer Physics, Early View Online, 2014. [DOI]
  3. A.A. Patil, M. Doxastakis, G.E. Stein, ``Modeling acid transport in chemically amplified resist films,'' Advances in Patterning Materials and Processes XXXI: Proceedings of the SPIE, 90511M, 2014. [DOI]
  4. Z. Qiang, L. Zhang, G.E. Stein, K. Cavicchi, B.D. Vogt, ``Unidirectional alignment of block copolymer films induced by expansion of a permeable elastomer during solvent vapor annealing,'' Macromolecules, 47, 1109-1116, 2014. [DOI]
  5. J. Cushen, L. Wan, G. Pandav, I. Mitra, G.E. Stein, V. Ganesan, R. Ruiz, C.G. Willson, C.J. Ellison, ``Inducing Order in Poly(trimethylsilyl styrene-b-D,L-lactide) by Solvent Annealing Using a Mixture of Domain-Selective Solvents,'' Journal of Polymer Science Part B: Polymer Physics, 52, 36-45, 2014. [DOI]
  6. 2013
  7. D. Sunday, M.R. Hammond, C. Wang, W.L. Wu, R.J. Kline, G.E. Stein, ``3D X-ray metrology for block copolymer lithography line-space patterns,'' Journal of Micro/Nanolithography, MEMS, and MOEMS, 12, 031103, 2013. [DOI]
  8. Z. Qiang, J. Xue, G.E. Stein, K.A. Cavicchi, B.D. Vogt, ``Control of ordering and structure in soft templated mesoporous carbon films by use of selective solvent additives,'' Langmuir, 29, 8703-8712, 2013. [DOI]
  9. E. Cacao, T. Sherlock, A. Nasrullah, S. Kemper, J. Knoop, K. Kourentzi, P. Ruchhoeft, G.E. Stein, R.L. Atmar, R.C. Willson,``Helium beam shadowing for high spatial resolution patterning of antibodies on microstructured diagnostic surfaces,'' Biointerphases, 8, 1-10, 2013. [DOI]
  10. E.E. Cacao, A. Nasrullah, T. Sherlock, S. Kemper, K. Kourentzi, P. Ruchhoeft, G.E. Stein, R.C. Willson, ``High-resolution, high-throughput, positive-tone patterning of poly(ethylene glycol) by helium beam exposure through stencil masks,'' PLoS ONE, 8, e56835, 2013. [DOI]
  11. M. Luo, J.E. Seppala, J.N.L. Albert, R.L. Lewis, III, N. Mahadevapuram, G.E. Stein, T.H. Epps, ``Manipulating nanoscale morphologies in cylinder-forming poly(styrene-b-isoprene-b-styrene) thin films using film thickness and substrate surface chemistry gradients,'' Macromolecules, 46, 1803-1811, 2013. [DOI]
  12. N. Mahadevapuram, J. Strzalka, G.E. Stein, ``Grazing-incidence transmission small angle X-ray scattering from thin films of block copolymers,'' Journal of Polymer Science Part B: Polymer Physics, 51, 602-610, 2013. [DOI]
  13. 2012
  14. G.M. Perera,* Y.N. Pandey,* A.A. Patil, G.E. Stein, M. Doxastakis, ``Reaction kinetics in acid-catalyzed deprotection of polymer films,'' The Journal of Physical Chemistry C, 114, 24706-24716, 2012. [DOI]
    • *Equal Contribution.
  15. G.M. Perera,* C. Wang,* M. Doxastakis, R.J. Kline, W.L. Wu, A.W. Bosse, G.E. Stein, ``Directed self-assembly of lamellar copolymers: Effects of interfacial interactions on domain shape,'' ACS Macro Letters, 1, 1244-1248, 2012. [DOI]
    • *Equal Contribution.
  16. S. Moungthai,* T.C.H. Pham,* A.A. Rajaendran,* G.E. Stein, ``Ordered arrays of polymer droplets with triangular, circular, and rod-like shapes,'' Soft Matter, 8, 10026-10031, 2012. [DOI]
    • *Equal Contribution.
  17. S. Moungthai,* N. Mahadevapuram,* P. Ruchhoeft, G.E. Stein, ``Direct patterning of conductive polymer domains for photovoltaic devices,'' ACS Applied Materials & Interfaces, 4, 4015-4023, 2012. [DOI]
    • *Equal Contribution.
  18. A. Labiano, M. Dai, W-S Young, G.E. Stein, K. Cavicchi, T. Epps, B.D. Vogt, ``Impact of homopolymer pore expander on the morphology of mesoporous carbon films using organic-organic self-assembly," The Journal of Physical Chemistry C, 116, 6038-6046, 2012. [DOI]
  19. 2011
  20. C. Wang, G.E. Stein, A.W. Bosse, W.L. Wu, ``Line edge roughness of directed self-assembly PS-PMMA block copolymers - A candidate for future lithography,'' AIP Conference Proceedings, 1395, 305-308, 2011. [DOI]
  21. T. Vu,* N. Mahadevapuram,* G.M. Perera, G.E. Stein, ``Controlling domain orientations in thin films of AB and ABA block copolymers,'' Macromolecules, 44, 6121-6127, 2011. [DOI]
    • *Equal Contribution.
  22. B.D. Vogt, V.L. Chavez, M. Dai, M.R. Croda Arreola, L. Song, D. Feng, D. Zhao, G.M. Perera, G.E. Stein, ``Impact of film thickness on the morphology of mesoporous carbon films using organic-organic self assembly,'' Langmuir, 27, 5607-5615, 2011. [DOI]
  23. 2010
  24. G.M. Perera, G.E. Stein, J.A. Liddle, ``Spatial coherence in electron-beam patterning,'' Journal of Vacuum Science & Technology B, 28, 1048-1055, 2010. [DOI]
  25. V. Mishra, S.-M. Hur, E.W. Cochran, G.E. Stein, G.H. Fredrickson, E.J. Kramer, ``Symmetry transition in thin films of diblock copolymer/homopolymer blends,'' Macromolecules, 43, 1942-1949, 2010. [DOI]
  26. G.E. Stein, J.A. Liddle, A.L. Aquila, E.M. Gullikson,``Measuring the structure of epitaxially assembled block copolymer domains with soft x-ray diffraction,'' Macromolecules, 43, 433-441, 2010. [DOI]
  27. 2005 - 2008
  28. C. Tang, J. Bang, G.E. Stein, G.H. Fredrickson, C.J. Hawker, E.J. Kramer, M. Sprung, J. Wang, ``Square packing and structural arrangement of ABC triblock copolymers in thin films,'' Macromolecules, 41, 4328-4339, 2008. [DOI]
  29. G.E. Stein, E.J. Kramer, X. Li, J. Wang, ``Thickness dependent ordering in laterally confined monolayers of spherical domain block copolymers,'' Macromolecules,  40, 5791-5800, 2007. [DOI]
  30. J. Bang, B.J. Kim, G.E. Stein, E.J. Kramer, C.J. Hawker, T.P. Russell, ``Effect of humidity on the ordering of PEO-based copolymer thin films,'' Macromolecules, 40, 7019-7025, 2007. [DOI]
  31. G.E. Stein, E.W. Cochran, K. Katsov, G.H. Fredrickson, E.J. Kramer, X. Li, J. Wang, ``Symmetry breaking of in-plane order in confined copolymer mesophases,'' Physical Review Letters, 98, 158302, 2007. [DOI]
  32. G.E. Stein, E.J. Kramer, X. Li, J. Wang, ``Layering transitions in thin films of spherical-domain block copolymers,'' Macromolecules, 40, 453-2460, 2007. [DOI]
  33. G.E. Stein, E.J. Kramer, X. Li, J. Wang, ``Single crystal diffraction from two-dimensional block copolymer arrays,'' Physical Review Letters, 98, 086101, 2007.  [DOI] (Cover)
  34. V. Khanna, E. Cochran, A. Hexemer,  G.E. Stein, G.H. Fredrickson, E.J. Kramer, X. Li, J. Wang, S.F. Hahn, ``Effect of chain architecture and surface energies on the ordering behavior of lamellar and cylinder forming block copolymers,'' Macromolecules, 39, 9346-9356, 2006. [DOI]
  35. A. Hexemer, G.E. Stein, E.J. Kramer, S. Magonov, ``Block copolymer monolayer structure measured with scanning force microscopy moire patterns,'' Macromolecules, 38, 7083-7089, 2005. [DOI]

Book Chapters
  1. G.E. Stein, ``Scattering methods for thin polymer films,'' In Functional Polymer Films: Characterization and Applications, R. Advincula, W. Knoll, Eds.; Wiley-VCH: Weinheim, 2011, pp. 669-694.

Outreach

Research Experiences for Undergraduates

The theme of our REU program is Innovations in Nanotechnology.

GRADE Camp

Girls Reaching And Demonstrating Excellence, Summer 2011

Materials Day

Participants from North Shore High School, January 2012

Mars Rover Day

Participants from Houston area middle schools, January 2012